Inflammation and Immunity in Dermatophytosis

Abstract

Infections by dermatophytes (dermatophytosis) naturally stimulate the immune system as in those by other microorganisms to induce various immunological phenomena. However, differing from other infections, the infecting organisms cannot become a direct target of antibody response or phagocytosis because they reside only in the barrier membrane of the body surface, i.e. in the stratum corneum.Thus, the immunity against dermatophytes is relative as compared with the absolute one noted in other infections such as measles and mumps. In dermatophytosis, a unique behavior of the epidermis as noted in contact dermatitis plays an important role in the defense against infection. Dermatitic changes induced by fungal products, particularly those due to contact sensitivity to a fungal antigen, trichophytin, enhance epidermopoiesis, which leads to increased turnover of the epidermis with their resultant elimination from the skin surface. Furthermore, the dermatophytes in the stratum corneum provoke transepidermal leukocyte chemotaxis by generating chemotactic C5a anaphylatoxin in exudating serum via alternative complement pathway activation in addition to a release of low molecular weight chemotactic factors. Such neutrophilic migration with the formation of subcorneal pustules also enhances epidermal proliferation as in psoriasis.

Ultrastructural Alterations In The Epidermis Of Patients With Tinea Pedis

“…Furthermore, we observed migration of lymphocytes and PNL's between keratinocytes in stratum spinosum. A variety of mechanisms, such as complement activation by the alternative pathway and lowmolecular-weight chemotactic factor production, have been described to elucidate the mechanisms by which infl ammatory cells are attracted to the sites of cutaneous fungal infection (7,8,11,17,23,24). Our ultrastructural observation of migration of leucocytes is also consistent with the light microscopic fi ndings of epidermal lymphohistiocytic infi ltration frequently encountered in spongiotic dermatitis (8).…”

Majocchi’s Granuloma (Dermatophytic Granuloma): Updated Therapeutic Options

“…The NSFI plays an important role by suppressing the growth of dermatophytes and limiting their penetration into the dermis. This factor is also associated with the unsaturated transferrin, related to inhibition of dermatophytes by binding to iron, which is required for fungus growth [47][48][49][50].…”

“…Moreover, in regard to the PED, its function is to block the invasion of dermatophytes to the dermis; the major components of PED are the production of keratin, epidermal turnover rate, and the degree of hydration of the skin, the lipid composition of the stratum corneum, the CO 2 tension, and the presence or absence of hair [47].…”

“…Within the dermis, the alkaline medium and the keratin present in the injured follicle provide a suitable substrate for fungus growth [47].…”

“…Fungi release low molecular weight chemotactic factors that directly fix complement and thus increase the inflammatory response, especially neutrophilic [47].…”